Clad metal and process of producing the same.



W- M. PAGE & W. TASSIN.

GLAD MET AL AND PROCESS OF PRODUCING THE' SAME.

' APPLIGATION FILED rum, 1911.

Patented Jan. 19, 1915.

4 SHEETS-SHEET 1'.

W. M. PAGE 11w. TASSIN.

GLAD METAL AND PROCESS .OF PRODUCING THE SAME.

APPLICATION FILED FEE/8. 1911.

Patented Jan. 19, 1915.

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awe/M041 \D M 9 amw \bwcTclssaw /f% I I M pg g x W. M. PAGE & W. TASSINfGLAD METAL AND PROCESS OF PRODUCING THE SAME.

Patented Jan. 19, 1915.

APPLICATION FILED PEB.8, 1911.

4 SHEETS-SHEET 3.

l I l l 1 l ll I 3mm ns 8 AA WW v 44 L fi? W. M PAGE '& W. TASSIN. GLADMETAL AND PROCESS OF PRODUCING THE SAME.

' APPLICATION IILED F113. 8, 1911\ 6Q, Patented Jan.19, 1915.

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WILLIAM MARSHALL PAGE, or RIDLEY rAnK. AND wrnr-rnssrn, or CHESTER,PENN- SYLVANIA;

1,125,160. riginal application filed April 28,1910, Serial No.

GDAD'METALAND PROCESS Oil?"' IE-B101)tlCIlEhTG THE-.SAME.

Specification of Letters-rattan 5584198, Divided augl this, applicationfiled, February 8,1911, Serial'NmfiDZMii tively, Improvements in ofProducing the Same, ing is a, specification.

This invention relates to clad metals and processes of producing thesame; and it] comprises a body of copper clad steel having a core orlayer of steel eld united to. a

body or layer of copper. having a highelec of producing such metal andtrical conductivity, a good mechanical strength and a certain peculiartexture: evinced on polishing and etching, a section of such copperexhibiting a relatively coarse and flaky or platy macrostructure, freeof visible lines of demarcation or cleavage between the component platesor flakes, such plates or flakes under the microscope ap-. pea ringintegrally united and each such plate or flake showing very smallisometric crystals regularlyv arranged and having the same lines oforientation in any one plate though having different lines in adjacentplates or flakes and it also comprises a method ofproducing such copperclad steel wherein a body of copper is treated while in a molten statebyremoving oxygen and oxids by solution therein of a more oxidizablemetal,.such as iron, and thereafter removing the dissolved oxidizablemetal, and is thereafter Weld united to a body of steel; all as morefully hereinafter described and as claimed.

For commercial purposes, firmly unitedbodies of compact copper and steelhave long been a desideratum. Galvaniccoatings and the like are porousand unsatisfactory, and Will not stand Working. It isSdifficult toproduce a firm and permanent union, of the nature of aweld union,between copper and steel, they being unlike metals. Such metal hasrecently been roduced' (see Part. ents 853,716 and 893,932 and is nowcommercially available. The present invention relates to an improvementin the methods to an improved compound metal. Copper cladsteelof thecharacteristics indicatedin Patent,

ware and State of Peiinsylwania, 'le iwil v usef l for verymanypurposes, The; copper oating s jmp yieuaan may be worked. atthe, sametimewlth and, in'the'same manner as thebe attached; A billet may bevoated. and. then worked; down to fine wire, 4

heets a d the. l k w theut. p re of h 410. between. the. metal and; e ain metal, is mproved in its texture and charaeter stlcsby the working.down. For he. urrows" or whi h. such c a meta is fiigl fid h. 'SIdesirable... that the copper,

hi h-1S ordin -pla en; uter coating, should be as impervious. andcompact, as possible. llyipqr filty leads; to lack. of strength and tothe possibility of air W 1-corros'ive fluids reaching'the underlyingsteel and producing corros on, Much of; the copper? clad metal is usedfor. electr cal purposes, and it is thereore also desirable'that. thecoating shall.

have as. high a oonductiyity as possible- Ordinary copper is-howeverusually moreor s mp r onta mg Q i a g es;

both ina state of, solutiomandina state of mechanical admixture. The coper is usually not quite homogeneous. an "ismore or less porous. Much ofthe perosity is re.-

movedin the ordinary; methods of- Working.-

. down copper clad Steel, but some is apt remaln'.

.In the present, invention copper is pre hmmaraly treated prior toattaching it to the steel n such manner. as .to make it hollyhomogeneous, of good mechanical strength,

impervious and compact, and of high electrical. conductivity, renderingit much more suitable as a. con1 ponent of copper clad steel. Copperhaving the characteristicsof the metal of the present invention exhibitsa peculiar macrostructure andmicrostructure, rendering .it easilyidentifiable. 3 For the purposeofthis. preliminary treatment, the

molten: copper is first treated by dissolving iron or steel therein.This treatment. may

- be, and advantageously is, "a part of the operation of producingcopper clad steel. On-

solutionrof-iron or steel in copper, all the oxygen and 'oxids areremoved. The iron combines with the free oxygen present, and also withthe oxygen of the oxids present as impurities,'forming iron oxids which,relative to the copper, are of. light specific gravity and rise readilytothe. surface of molten coppen- The, copp r: thustreated is how- S93,932 is ever not. directly-suitable for the present.

S purposes. The ironwhich it contains while giving it greater mechanicalstrength than .that of pure copper, nevertheless "runs down itsconductivity inordinately. The ironcontaining coppen for the presentpurposes,

should therefore nextbe treated to remove the excess of iron, This maybe readily done by covering the surface of 'the moltenferruginous'copper with a layer of floating carbon, such as charcoal,coke breeze, etc., and then impinging or approximating a flameupon theprote cted'surface. -Under these conditions the iron in the copper burnsout at 'the expense of the oxygen, carbon monoxid, carbon dioxid, etc.,of the flame without'anoxidation of-the copper ensuing and withoutreabsorption of oxygen by such copper. With the hot flame gases incontact with the carbon floating 0n the copper, the copper" ispracticallyblanketed by an atmosphere of carbon monoxid a'nd'carbondioxid, both of which,- under the circumstances, are 'oxidants for ironwhile not oxidizing copper. The copper is now perfectly pure and of apeculiar macrostruc ture and ni1crostructure, as hereinafter de scribed.p

"A convenient way of effecting the described operation by a solution ofiron and removal of excessfis to use a tilting furnace which may be ofthe typeof-that'described in Patent 929301-01 in the.. co-pending application -of one of us, Seri'alNo. 516,253.

In both types offurnace, a tilting furnace chamber is provided with arelatively deep pocket and with. a shallow hearth., By

transferring the molten coppertojthe deep 'pocket, a bar of steel can bepassed beneath the surface. The temperature of the copper may be abovethe melting point of steel. Iron being lighter than copper, the irondissolved or melted off the surfaceof the bar tends to rise-throughthecopper, giving a good and efiective' contact between the two metalsfor the present. purpose. The bar or body of steel inserted maybe thatwhich is snbsequentlyto be coated with copper in producing a cladbillet. In this operation it may also be given a film coating of copperor copperiron alloy (Patent 853,716). In this treatmentwith iron orsteel, the metalloids and metals ofthe steel also have a reducing effectupon the copper. Carbon, silicon, phosphorus, and the like, tend toreduce the oXids-and oxygen of the copper in the same manner as iron.Their amount -in the steel is usually relatively small but insofaras'they are present th ey have the same reducing-function'as the iron.

They do not, however, remain in solution in the copper to any extent.The .molten copper, which now contains iron but is free of otherimpurities, is nextjransferred back to the shallow hearth and is coveredwith floating carbon. A flame is then impinged a aaaoc upon orapproximated to the surface o f the;

provided with a thin, firmly attached coating of copper or copper ironalloy. The picking is best done with a halogen acid,

such as hydrochloric or hydrofluoric acid. On dlpping the cleansedbillet into a bath of highly heated molten copper, a thinclinging filmof copper iron-alloy is formed and the billet may be withdrawn coveredwith this film. After the cleansing, it is best maintained in a casingfilled with an inert gas, such as producer gas or nitrogen, and it isbest withdrawn from thefilming bath, into the same atmosphere to preventfilming operation may be the same as the first o eration ofpurifying thecopper. Where it is not and where the bath. is used for filming a numberof billets, it soon becomes largely a molten copper-iron alloy fromithesolution of iron therein. Such copper iron alloy is, however, as goodfor filming a billet as pure copper. And as the thickness of this firstfilm should always be relatively small, the presence of iron in it doesno great harm, even where the clad burning off the alloy film. -Asstated, this I metal .is used for electrical purposes, and

probably does some good because of the -mechanical strength of thecopper iron alloys.

Copper'clad iron for electrical purposes is generally used for overheadconductors where a maximum strength must be combined with a maximumconductivity. For:

this purpose, the core should be of a good, sound, strong steel andthemain body of the coating should be of the special purified copper whosemanufacture has just been described, the two being linked together bythe film coating just described. This filmv coating serves as a linkingmember or anexus; it. is a layer which should be thin, 'and which isintegrally united with the copper on the one side and the steel on theother.

Other ways of -making the film coating.

may be adopted. For' example. after sand blasting and pickling, thebillet may be treated to prodrzpe a surface of pure iron thereon,pureiron uniting more readily with copper than does steel and at lower andmore convenient temperatures. The billet mav. for example, be oxidized,and afterward reduced, as by producer gas or the llSt dized surface pureiron is produced. Ana

other convenient way (of operating is to treat the pickled billet withsuperheatedstreaming steam to produce a cohering thin coating ofmagnetic mud on. its surface.

On now dipping the treated billet in molten moreor less dlagrammaticallycertain views copper, the oxygen of the oxid coating and the carbon ofthe underlying steelreact to form oxids of carbon and pure iron, thispure iron coming bothfrom the layer of oxid and from the underlyingsteel which has been robbed of itscarbon. The pure iron thus roducedunites very readily with copper. imilarly, though not so advantageously,a billet covered with mill scale may be used.. Rusted oxid coatings arenot suitable. Millscale is also magnetic oxid,

but the coating of scale does not cohereto the steel as uniformly andthoroughly as that produced by. streaming steam in the way described. Further,'there isapt to beadhering sand, silicate, slag, etc., which aredifficult to remove in the case of a billet 7 covered with mill scale,and there may also be porosities in the coating. Magnetic oxidon dippinginto impure copper has in. a measure the same oxygenremovmg propertiesas iron, since ferrous oxid, which is a component of magnetic oxid, hasthe power of reducing oxids 'of 'copper. Where the copper is of thecharacter known as underpoled that is, contams much'dlssolved oxygen,the clean steel -may be directly dipped in it and the oxygen of thecopperand the carbon; of the superficial layers of the steel will unite,leaving pure iron to combine with the copper.

In a specific embodiment of the present process, a billet may besandblasted, pickled,

and exposed to superheated streaming steam until the described oxidcoating is produced. The oxidized billet may then be dipped into a bodyof impure copper in the well or pocket of a tilting furnace; By a properadjustment of time, temperature, and other conditions, the copperwillbepurified. of oxygen and oxids and the billet covered with a clingingfilm of copper iron alloy. The copper, which may now contain iron inexcess, may then be flowed back, upon a shallow hearth and purified asdescribed after which it may be cast into proximity 55 to the filmedbillet previously produced to form the main body of the coating of suchbillet. Or, by regulating conditions, the. amount of iron dissolved oilthe billet. in" the filming operation may be substantially that which isrequired to'remove the impurities. from the copper without g ving anysubstantial excess of dissolved iron, inwhich case the purified coppermay be directly used forthe main coating. It is,

6 however, usually more convenient to film number of ,bille tsin .J.body of co er until the copper is pure," except as regards iron, andthen purify the copper for coating purposes, coating the filmed billetsas fast as produced from another body ofcopper which has undergonethepurifying operation previously. y

In accompanying illustrationsare shown of sections of metal, and certainillustratrans. of apparatus elements useful in the descrlbejd process.In the showing, the views of the-metal are as near a reproduct1on of theoriginal .photomicrographs as the limitations of Patent Oifice drawingspermit.

: Figures 1 and 2 show vlews on an en-.

larged scale of polished and etched masses of ordinary copper. ofdifferent brands; Fig. 3- is a similar section of an ordinary commercialwire bar; Figs. .4, 5 and 6 are representations on a similar .scale ofami- QI'OSQOPIQ. appearance ofthe copper of'the coating m' acompound-.met'al of the pres-v ent invention; Fig. 7 is a viewpfthe'same' copperafter having undergone a reduction to it lnch rod; Fig.8 is a view taken across the line of union in clad metal under thepresent invention, showing the steel and In the showing of the metalsections, the

- enlargementiis the same in each view, such enlargement being 270diameters. The

views are,- as nearly as possible, a repro' ductionof originalphotographs on file in,

application Serial No.

our co-pending -.55s,093. 1 In th howing of Fig. 1-, the metal is anexcellen quality of commercial copper showing. but littledifferentiation in texture.

The showing of Fig. 2 is that of a lower grade of commercial copper. Thewhite and the black areas are both copper, while the black spots arepittings and oxids. .By

careful examination of the view it will be noticed that there"a re linesof demarcationand separation between the crystals or areas of copper,and these lines contain more or less oxid of copper. Fig. 3 is a similarview of a sample of ordinary wire bar of fair quality.

" Figs. 4. 5 and 6 show asnearly as possible] within the limits ofphotography, the peculiar optical appearance under the microscope of asection of the new copper. After the new copper is well polished and is'etched'somewhat it displays to the eye a peculiar flashing appearanceas if the surthis parallelism very clearly. Fig. 7 shows of copper ironallbys.

with port 10 adapted to be closed by swingcharacteristic andverydistinctive is hard to reproduce. On enlargement as in these views, thisstructure is less evident but the sets of parallel crystals togetherform the flake-likeareas visible to the naked eye.. In

these views the flakes are resolvedinto a mlcrostructure of parallelisometrlc crystals regularly arranged. Figs. 5 and 6 show a microview ofthe'same copper after the compound metal has been drawn out to 5 inchrod. 111 drawing out and working down the copper, the peculiar structurewhich exists in the original billet of clad metal is, of course, changedconsiderably. Fig. 8 shows a view on the same scale of a clad metalbillet, the view being taken across the line of joinder. The upper oromo-' geneous looking area is the copper an the lower is thc'steel. .l'npolishing a sa nple such as this, it is difiicult to adopt a method ofpolishing and etching which will show the peculiar microstructure ofboth metals. Between the upper copper area and the lower steel areais'shown a band or layer Upon examination this band will be seen to havean upper blackish area which is a high copper alloy. Below this aregrayish areas of various coper iron alloys and below these again there1s a layer of high iron alloy. That is, there is a layer of high copperalloy next the copper, and a layer of high iron alloy next'the steel.Thecopper extends more or-less into the edge of the iron area.

In the apparatus shown in Fig. 9, element 11 is a metallic casing of anysuitable material lined with refractory material 2, and having a centralflame and treatment chamber 3. Communicating with this chamber areducts4 set at an angle and communicating with chamber 5 for moltenmetal. This furnace chamber is arranged to be tilted on a horizontalaxis andt'o facilitate tilting it is provided with bearings 6, and ashoulder T provided with lever arm 8 carrying a weight receiving device9 to aid in counterbalancing. At one side opposite the metal duc't'thefurnace chamber is shown provided ing door 11. 12 and represent theframework carrying the furnace. S Oil pipe 14 (see Fig. 10) provides forfiring at either or both ends of the flame chamber by means of valvedpipes 15 and 16 feeding burner 17 providedwith air or steam injectingmeans 18. i

The fragmentaryshowing in Fig. 11 is of the same furnace structure indipping or purifying position, but above the pocket is shown mountedasegregating or dipping casing 19 provided with means 20 for introducingproducer gas or other inert atmos phere and hoisting means 21 and 23 maybe employed. This casing surrounds billet 22 which may have beensandblasted or otherwise treated and is provided. with an end cap 24adapted to make a tight joint with the bottom of the casing and an inlet25 provided with sealing means 26. This sealing means may be a ring ofasbestos or metal which is adapted to be pushed aside when the orificeis to be used for the introduction of metal. The billet may be coatedeither in the dipping casing-just described or in a special mold, suchas that shown in Fig. 9.

For the use of this mold the dipping pocket of the furnace may beprovided witlra pouring lip 27. The mold indicated at 28 is shown ascontaining a filmed billet 29 and as surmounted by a protective casing30,

carrying gas feeding means 31 and used to shield the billet during theclipping opera .heat ofmolte'n copper and will act as a cleansing agentupon molten copper poured therethrough. i

In the use of the structures shown in Figs. 9, 10, 11, copper may bemelted in the chamber 3 by the oil flames from 18. The furnace may nowbe tilted and-iron introduced-in the copper in chamber 5, best bydipping a billet or rod therein. The copper for this operation is bestat a'temperature above the melting point of steel. The steel melting anddissolving in the copper frees it effectually of,oxygens and oxids,while by dipping the relatively lighter steel in the relatively heaviercopper the molten particles of steel upon rising flow through the copper-and give a good distribution of iron therein. By carefully controllingthe conditions of the operation merely enough steel may be brought intosolutionto remove oxygen-and oxids, leaving the copper pure. Ordinarilyan excess is introduced. Upon now tilting the furnace back into thepurifying' position and introducing a layrr of 'fioat'ing carbon uponthesurface 9f the copper,' upon heating with the "oil flame, thisexcessof iron burns out,leaving copper of the nature described. Uponagain tilting the furnace the purified copper flows out into chamber 5whence it may-be cast through 27, into the ingot mold 28. Gr insteadofcasting directly from the furnace,

the purified copper may berun into ladles "mam-e 7 1 a and cast. frbmthese around the filmed billet in mold 28. I

filmed billet in a separate ingot mold asabove described, the coatingoperation may also'occur in chamber 5. Thus after hav-' ing been filmed,the billet with the base plate 24 attached may be withdrawn from chamberinto casing 19, the joint between the plate and casing being sealed byasbestos packing or other suitable means. An inert or deoxidizingatmosphere is con stantly maintained Within the casing by introductionof a suitable gas in order to protect thenewly formed copper filmagainst oxidation. The body of copper in chamber 5 having been purifiedby treatment in '3, or'a similar body of copper bein already at hand ina second furnace, the lmed billet with its surrounding :casing isplunged into chamber 5 so that the orifices '25 are below the. surfaceof the molten copper. Closures 25 are remev'e'd so as to uncover theorifices inthe casing, whereupon copper flows into the casing and fillsthe space between it and .theffilmed billet, afterrwhich the casing andbillet are withdrawn from chamber 5 and 4 readily uniting withthe'filmon the billet to form a substantial coating of copper weldallowed to cool, the 'copper thu s trapped united to. the ferrous metalcore. This method is very simple and is of specialutility in makinro'undcopper clad billets. In applying th1s substantial coating, thetemperature of the molten copper may be, and advantageously is, somewhatlower, than in forming the film coat. This. is for the reason that theunion of copper to the copper or the copper-iron alloy of the film onthe billet readily occurs at temperatures below that necessary for theunion of coper and iron 'or steel, while if excessive y hot copper wereemployed in forming thls substantial coating, the very hot copper mightmelt oil the copper iron alloys on the surface of the billet andbecome'contaminateda In ordinary working, the billets may be filmed inone apparatus and the ure copper applied in another, the pieces 0apparatus being alternately used for dipping and forforming thesubstantial coat. Operating thus, the billets may be dipped into thecopper until enough iron has dissolved therein to remove allimpurities,, the purified copper then freed of iron in themannerdescribed, allowed to fall in temperature and .then used forforming coatings.

By careful adjustment of working conditions, the billet to be filmed maybe allowed "-to'remain in the supermolten copper in the preliminarydipping just long enough to supply the amount of steelrequisite tocompletely reduce all copper oxids in the bath,

without any, excess of ironbe'ing dissolved.

The copper thus purified by the filming step may be allowed to coolsomewhat and then cast against the filmedbilletas describedto of veryhotcopper is contained in' a comparatively small dlpplug vessel and therela- 'tively cooler billet dipped therein, the first action is that ofheating the surface of the billet to a very high temperature. At thistemperature the solution of the iron, the reduction. of the iron oxid,Where such is present, and the purification of the copper all go on atonce. As theheat penetrates inward in the billet, the temperature of thesurrounding copper drops until it reaches the desiredlower temperature,whereupon this copper niay be directly applied to the 'filmedbi-llet.For some purposes, a convenie'n-t method of operation is to run very hotcopper into a relatively small hot dipping p'ocketor container, dip abilletthereiutountil, the copper is purified and the surface of thesteel covered with Welded-on copper, and then follow by dropping aroundthe billet a mold casing'adapted to inclose ing billet; casing andcontained coppertogether. The apparatus shown in Fig. 11 is convenienttouse in' carrying. out this modifiediprocess. Ordinarily it is betterto per form the filming and coating operations in two separate stepsrather than to combine them as just described, for the reason that it isdifiicult in the one-step process to obtain the requisite bodv of thecoating.

What we claim is f 1. The process :of preparing copper clad steel whichcomprises treating copper in a highly heated molten condition with iron.in excess of the amount'sufiicient to react with oxygen and oxidspresent, removing such excess and then producing a solidified purity ofcopper inthe main .7

body of suchcopper united to a body of ferrous. metal.

2, The process of producing copper clad cient iron to remove oxygen andoxids present, removing any excess of irbn which may be present, filminga steel object with a copper coating and producing asolidified body ofthe treated copper umted to the filmed steel object. 1

. 3. The process .of forming copper clad steel which comprises bringingabo'dy of molten copper to a temperature 'in excess of that required tomelt steel, dipping a body of steel into such copper until sumcient ironhas dissolved to remove oxygen and oxids, burning out the excess of ironby preferential oxidation and forming? a solidified bod of the treatedcopper unite'd to a body of errous metal.

4. The process of forming copper cladv burning out the excess of iron bypreferential oxidation, producing a Weld-film of copper on a stee objectand forming a solidified body of the treated copper united to such steelobject through such weld-film.

5. The process of forming copper clad steel which comprises producing ahighly heated body of molten copper, dipping a billet into. the. sameuntil dissolved iron removes oxygen and ox-ids and uniting the purifiedcopper to a steel billet.

6. The process of forming copper clad steel which comprises removingoxygen and oxids'from molten copper by dissolving iron therein andproducing a solidified body of the purified copper united to a body offerrous metal.

7. As a new article of manufacture, a clad metal'article havin a body ofsteel weldunited to a body out copper through an intervenin layer ofalloyed copper and iron, such be y of copper upon polishing and etchingexhibiting a relatively coarse platy or flaky macrostructure andmicroscopically examined displaying a crystal structure of regularlyarranged isometric crystals having the same orientation within any oneflake or plate, the lines of orientation Within adjacent flakes orplates not being the same,

but displaying no apparent line of cleavage or demarcation between suchadjacent flakes or plates. Q

8. As a new article of manufacture, a clad metal article having a bodyof steel weld united to a body of copper through an intervening. layerof alloyed copper and iron, such intervening layer comprising a stratumof a high copper alloy next the said body of copper, and a stratum of ahigh viron alloy next the said body of steel.

WILLIAM MARSHALL, PAGE. wrnr rnssrn.

Witnesses:

P. M. W'nrs, J. BRUN'DAGE.

